|
| |
|
|
A133520
|
|
Smallest k such that p(n)^4 + k is prime where p(n) is the n-th prime.
|
|
8
|
|
|
|
1, 2, 6, 10, 12, 10, 16, 16, 6, 12, 18, 16, 12, 28, 6, 22, 6, 16, 6, 16, 6, 16, 30, 6, 16, 42, 22, 42, 28, 52, 22, 16, 28, 10, 28, 70, 30, 42, 78, 36, 12, 42, 6, 12, 40, 12, 12, 16, 16, 16, 18, 10, 6, 22, 60, 46, 76, 46, 18, 126, 12, 22, 22, 6, 16, 16, 22, 18, 120, 22, 12, 6, 6, 36
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
LINKS
|
Harvey P. Dale, Table of n, a(n) for n = 1..1000
|
|
|
EXAMPLE
|
p(2)=3, 3^4 = 81; for odd k and n > 1, p(n)^r + k is even and thus not prime, so we only need consider even k.
for k = 2: 81 + 2 = 83, which is prime, so 2 is the smallest number that can be added to 81 to make a new prime.
Hence a(2) = 2.
|
|
|
MATHEMATICA
|
NextPrime[#]-#&/@(Prime[Range[80]]^4) (* Harvey P. Dale, May 17 2015 *)
|
|
|
CROSSREFS
|
Cf. A030814, A054271, A091666, A133517, A133518, A133519, A133521, A133522, (A001223).
Sequence in context: A125241 A116043 A085258 * A099017 A298748 A139799
Adjacent sequences: A133517 A133518 A133519 * A133521 A133522 A133523
|
|
|
KEYWORD
|
easy,nonn
|
|
|
AUTHOR
|
Carl R. White, Sep 14 2007
|
|
|
STATUS
|
approved
|
| |
|
|
